Re: NEC-LIST:Band width of Yagi

Dear Zvi

I have simulated a couple of yagi's using SuperNEC's Genetic Algorithm
optimiser. I have listed the results below. Please contact me if you require
any of the antenna parameters for any of the designs listed below:
All the yagi designs below use elements with a 0.008m radius, a folded
dipole feed, directors of all equal length, spacing between directors all
equal, and the design frequency was set to 300Mhz.

-5 element yagi(vswr for 75ohms)
Gain BW 22.3% VSWR<2 BW 8.7% gain @ 300Mhz 10.19dBi
Gain BW 21.7% VSWR<2 BW 5% gain @ 300MHz 10.4dBi

-6 element yagi (VSWR for 75ohms)
Gain BW 14% VSWR<2 BW 5.7% gain @300MHz 11.62dBi

-12 element yagi (VSWR for 200 Ohms)
Gain BW 29.3% VSWR<2 BW 20% gain @300MHz
12.11dBi

-15 element yagi (VSWR for 200 Ohms)
Gain BW 11.3% VSWR<2 BW 11.3% gain @ 300MHz 15.38dBi
Gain BW 14% VSWR<2 BW 12.7% gain @ 300MHz 14.61dBi

-17 element yagi (VSWR for 200Ohms)
Gain BW 15.7% VSWR<2 BW 11% gain @ 300MHz 14.59dBi
Gain BW 17.3% VSWR<2 BW 12.7% gain @300 MHZ 13.97dBi

where %gain BW = ((Fh-Fl)*100)/Fc
where Fc=300MHz(design frequency) Fh=highest frequency at which gain is 3dB
lower than gain at Fc and Fl=lowest frequncy at which gain is 3dB lower than
gain at Fc

Regards
Brandon

Sent: Sunday, June 16, 2002 5:20 PM
Subject: Re: NEC-LIST:Band width of Yagi

:
> > > HI All,
> > > This is probably an old question but what is the bandwidth of
a
> > > YAGI. As far I know it is very small . Is there away of broadening the
> > > bandwidth ? How much can one get ? For low Gain YaGI's (3 or 4
elements) Is
> > > the bandwidth wider ?
> >
> >

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